Performance-Energy Trade-off in Multi-Server Queueing Systems with Setup Delay
Abstract:
In this talk we review some recent results related to the performance-energy trade-off in multi-server queueing systems, where the servers have multiple energy states. In addition to the normal BUSY and IDLE states, a server can be switched OFF to save energy. However, switching the server again on results in a SETUP delay which consumes additional energy and deteriorates performance. For a single server system, we consider optimal strategies to switch the server off and on. Multi-server systems may have a central queue, or they may consist of parallel servers with their own queues. Switching servers off and on in a reasonable way is the main objective. In a system with parallel servers, one should also consider the dispatching (a.k.a. task assignment) problem: an arriving job is to be routed to one of the parallel servers. Here we present a size- and energy-aware MDP approach to solve the problem.